1. Field of the Invention
The present invention relates to a ratchet wrench, and more particularly to a ratchet wrench including an improved and simplified structure for being easily and quickly manufactured and assembled and for being easily operated or actuated by the user without an actuating knob or switch.
2. Description of the Prior Art
Typical ratchet wrenches comprise a head with an aperture there-through having ratchet teeth thereon, a drive member mounted for rotation relative to the head and defines a slide surface facing the ratchet teeth on the head, a pawl positioned between the slide surface and the head with the pawl having two sets of ratchet teeth for determining the driving direction of the drive member by the head.
For example, U.S. Pat. No. 4,520,697 to Moetteli discloses one of the typical ratchet wrenches also comprising a drive member mounted in the aperture of the head for rotation relative to the head, a pawl also mounted in the head and positioned for engaging with the ratchet teeth of the drive member in order to determine the driving direction of the drive member by the head, and two pins attached to a rotatable plate for actuating the pawl to control the driving direction of the drive member by the head.
However, the two pins are required to be extended out of the head and/or the drive member for being actuated or operated by the user and for controlling the driving direction of the drive member by the head.
U.S. Pat. No. 4,553,453 to Dempsey et al. discloses another typical ratchet wrench comprising a quick release mechanism, a continuous, uninterrupted friction wheel assembly mounted in the cavity of the wrench head for rotation relative to the wrench head, and a thumb actuated reverse mechanism provided for controlling the driving direction of the friction wheel assembly by the wrench head.
However, the thumb actuated reverse mechanism also includes a plunger that is required to be extended out of the friction wheel assembly and/or the wrench head for being actuated or operated by the user and for controlling the driving direction of the friction wheel assembly by the wrench head.
U.S. Pat. No. 5,255,576 to Keith discloses a further typical ratchet wrench comprising a ratcheting mechanism and a multi-configurated socket with adjustment bolt for opening and closing fire hydrant valves and removal and replacement of hydrant caps of various shapes and sizes, a pawl mounted in the ratcheting handle for determining the driving direction of the ratcheting gear by the ratcheting handle, and a pawl actuating lever is required to be coupled to the pawl for controlling the driving direction of the ratcheting gear by the ratcheting handle.
However, the pawl and/or the pawl actuating lever are required to be extended out of the ratcheting gear and/or the ratcheting handle for being actuated or operated by the user and for controlling or determining the driving direction of the ratcheting gear by the ratcheting handle.
U.S. Pat. No. 5,878,635 to Hsieh discloses a still further typical reversible ratchet wrench comprising an annular wheel mounted in a box end, and two pairs of stop plates mounted in the box end and biased to control or determine the driving direction of the annular wheel by the box end of a wrench handle.
However, the typical reversible ratchet wrench includes a one-way ratchet mechanism that may not be easily controlled or changed to the reverse drive direction.
U.S. Pat. No. 6,131,489 to Yang discloses a still further typical reversible ratchet wrench comprising an adapter mounted in a box body, and a driving block also mounted in the box body and selectively actuatable to engage with the adapter in order to determine or to control the driving direction of the adapter by the box body.
However, the driving block is required to be extended out of the box body for being actuated or operated by the user and for controlling or determining the driving direction of the adapter by the box body.
U.S. Pat. No. 6,155,140 to Tsai discloses a still further typical reversible ratchet wrench comprising a gear mounted in a notch of a head, and two pawls also mounted in the head for engaging with gear and for controlling or determining the driving direction of the gear by the head of the handle.
However, the gear may only be rotated or driven in one direction or unidirectionally, and the head of the handle should be disposed up-side-down for allowing the gear to be rotated or driven in the other direction by the head.
U.S. Pat. No. 6,295,899 to Lee discloses a still further typical reversible ratchet wrench comprising a barrel mounted in an opening of a head, and a number of drive inserts slidably engaged into the barrel and engageable with the curved and inclined or helical surfaces of the head, and a ring attached or mounted to the barrel for rotating the barrel and the drive inserts relative to the head and the fastener to be rotated or driven by the head of the wrench handle.
However, the barrel and/or the drive inserts are also required to be operated or actuated by the user in order to determine or to control the driving direction of the barrel and the fastener by the head of the wrench handle.
The present invention has arisen to mitigate and/or obviate the afore-described disadvantages of the conventional reversible ratchet wrenches.